Place the chopped cucumbers in a colander with a bowl underneath to collect the juices. Sprinkle a little salt on the cucumbers and set aside for 10 minutes. After 10 minutes, press down on the cucumbers to release their juices. Set the juices aside. This step helps you control the amount of liquid you add to the yogurt rice while not wasting all of the delicious flavor of the cucumbers.
Cook the rice. You can use the microwave or, if cooking on the stovetop, bring 2 cups of water to a boil, add the rice, bring back to a boil, cover and cook for 15 minutes. Let the rice stand a few minutes before opening.
Measure out the reserved cucumber juices in a half-cup measure and add enough nondairy milk to make a half cup. Place this in a blender along with the tofu and the lemon juice and blend into a very smooth paste. If using cashew yogurt, you can skip this step.
Add the blended tofu to a bowl along with the cooked rice and cucumbers and mix well. If using cashew yogurt, add it now to the bowl with the rice and cucumbers and mix in the cucumber juices. You can add some nondairy milk if the rice is too dry. Your curd rice should have the consistency of a risotto-- a little runny and very creamy.
Heat the oil in a small skillet. Add the mustard seeds and, when they sputter, add the black gram lentils. Once they start to turn a light golden color, add the jalapenos and curry leaves. Saute for a few seconds, then add the peanuts and cashew nuts if using. Saute until the nuts are lightly golden.
Add the mustard seed-curry-leaf-nuts mixture to the bowl with the yogurt and rice and mix well. Add salt to taste.
Serve at room temperature or cold.